
It is hard to find out which measuring device is more accurate and precise, because of recent continuous development in technologies.
Here are the shortlisted top-10 Mechanical Measuring instruments as per their accuracy, Laser Interferometer is no. 1 on the list and can measure a nanometer.
- Laser Interferometer
- CMM (Coordinate Meausring Machine)
- VMM (Video Measuring Machine)
- ULM (Universal Length Measuring Machine)
- EHG (Electronic Height Gauge)
- Digital Micrometer
- Digital Vernier Caliper
- Outside Micrometer
- Vernier Caliper
- Steel Scale
Let’s discuss a brief technical discussion about these devices one by one.
Laser Interferometer
A laser Interferometer can measure 0.000001 mm using Interferometry technology. This Device is commonly used for the Calibration of ULM, CMM, EHG etc because of its high accuracy.

CMM
The full form of CMM is Coordinate Measuring Machine.
The term measuring machine means a single-axis measuring instrument. Such an instrument is capable of measuring one linear dimension at a time.
The term coordinate (in CMM) refers to the instrument/machine that is capable of measuring in all three orthogonal axes.
VMM
The full form of VMM is Video Measuring Machine. Some Advance Machines are more accurate than CMM but in general, CMM has greater accuracy than VMM.

ULM (Universal Length Measuring Machine)
Universal Measuring Machine is easy to use and could be employed for measuring multiple dimensions of objects or instruments.
UMM(Universal Measuring Machine) consists of a rigid bed called Universal Measuring Table which is a flow table or can be fixed according to requirement.
EHG (Electronic Height Gauge)
An electronic height gauge is used to measure vertical dimensions from the reference ground. Electronic Height gauge show a digital display for output results with a least count of 0.01 mm.

Digital Micrometer
Digital Micrometer is a very popular instrument these days because of its ease of compactness of taking an observation. Digital Micrometers can observe measurement in mm or inch depending upon our need basis.
Digital Vernier Caliper
Digital Vernier Caliper is an upgraded version of the Analog Vernier Caliper, which is a widely used linear measurement instrument with a least count of 0.01 mm, more accurate than Analog.
This Digital type of vernier is similar to the Analog Vernier Caliper Instead Dimension output in Digital Manner is more convincing than the analogue type.

Outside Micrometer
An external Micrometer is also known as an Outside Micrometer.
It is used to check the outside diameter of the circle by the means of an accuracy of 0.01 mm or up to 0.001 mm.
Vernier type Micrometer gives the highest acceptable accuracy of 1 micron such gauge is the vernier type micrometre.
Vernier Caliper
Vernier Caliper is a widely used linear measurement instrument with a least count of 0.02 mm. It is used to measure linear dimensions like length, diameter, and depth.

Steel scale
A steel scale is a single-piece linear measuring instrument. The steel scale indicates two units that are cm and inches, cm division on one side and inches, on another side.
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Impressive compilation of the top-10 accurate mechanical measuring devices! This blog provides a valuable overview of these instruments and their respective accuracies. The detailed descriptions and technical explanations are commendable. Thank you to the author for shedding light on these essential tools for precision measurements. Keep up the excellent work!